diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 9006ec29..c50813cf 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-            toolchain: stable
+            toolchain: 1.66.0
             components: rustfmt, clippy
             override: true
       - name: rustfmt